What is the difference between a 1-to-1 and 1-to-many relationship?

What is the difference between a 1-to-1 and 1-to-many relationship?

Approach: Compare mapping between entities.

1-to-1 means one record in Table A relates to one record in Table B. 1-to-many means one record in Table A can relate to multiple records in Table B.

Follow-up: How is a many-to-many relationship implemented?

Key concepts: foreign keys, cardinality.